Magpul Ronin: Buell 1125R of the future RideApart

Dissatisfied not only with the disappointing reality of the Buell 1125R. but also the company’s untimely death, Colorado-based Magpul has taken matters into its own hands and evolved the superbike into the visually stunning, pared-to-the-bone motorcycle they always knew it could be. The Magpul Ronin eliminates the 1125R’s bodywork and front end, replacing them with a girder set up and an integrated subframe, tailpiece and airbox cover. The changes aren’t just visual, but are designed to improve the steering and drop 50lbs from the wet weight too.

“We liked what Erik Buell was doing – thinking outside of convention

– but he was so function driven in his design that it left a lot to be

desired from an industrial design standpoint,” says Michael Mayberry one

of Magpul’s co-owners.

But what business does Magpul. a firearms accessory manufacturer, have talking

about and making motorcycles? “We’re a design and manufacturing house,

not just a gun company.”

They’re also motorcyclists, Michael and others

at the company were really excited when they heard Buell would finally

build a water-cooled superbike, but disappointed when it looked and

worked the way it did. Cut to last year and Grady Barfoot from Project M85 entered the picture. They shared a similar

The most obvious alteration is the linkage fork and its front-mounted

radiator. Not only were the stock side-mounted radiators hideously ugly,

but they were also inefficient, requiring airflow to bend 90 degrees to

both enter and exit. The new radiator is considerably smaller, yet

far more efficient at cooling as it’s now directly opposed to airflow

and free from the radiant heat of the engine. Mounting it on the fork

does turn it into unsprung weight, which isn’t an ideal engineering

solution, but the location of the 1125R’s front suspension in relation

to the engine leaves no room for a traditional radiator mounted on the

front of the engine.

Due to the nature of girder forks, unsprung weight is almost always going to increase in comparison to telescopic items, there’s simply more mass below the spring, and this affects the Ronin too. Even with the addition of the radiator, the entire front end weighs the same as the stock setup and Magpul says they’ve experimented with radiator placement both on and off the forks and there was virtually no effect to the dynamics.

The girder does brings mechanical benefits that overcome the negative of increased unsprung weight, the design increases the

leverage ratio acting on the setup’s suspension component: a Penske

monoshock. That eliminates stiction, leading to a smoother action.

Magpul has also taken the opportunity to add 13mm of trail to the fork,

which otherwise follows stock geometry. That brings the front end geometry in line with current sportsbike convention, improving steering feel.

The radiator hoses pass between the girders and under the steering stem,

but have been positioned so as not to affect the steering.

“We wanted to eliminate everything that was up and in front of the

rider’s view,” says Michael of the new cockpit. On top of all this is a

new cast aluminum handlebar and steering yoke with a dinky Motogadget

speedometer and the ignition integrated into it. Michael bemoans the

loss of the tachometer, but is looking at integrating race-style LED

indicators to replace it. The cast aluminum handlebars can be easily

Since the 1125R uses a fuel-in-frame design, the “tank” is actually a

carbon fiber airbox cover that now includes two ram-air intakes on its

leading edges. These have been repositioned from in front of the engine,

The effect created by the new bodywork works in conjunction with the

rearward-pointing triangle of the frame and swingarm to radically direct

the visual emphasis of the Ronin forward to the massive girder fork.

The 146bhp Rotax v-twin — unaltered – is also exposed and combines with

the angularity of the body and frame to create a look that evokes

mechanical function to replace the Buell’s downright awkwardness.

The Ronin is currently a functional prototype and Magpul’s first toe in